Related papers: Pions near condensation under compact star conditi…
We study the leptonic decay of charged pions in a compact star environment. Considering leptons as a degenerated Fermi system, pions are tightly constrained to decay into these particles because their Fermi levels are occupied. Thus, pion…
Pions may remain stable under certain conditions in a dense media at zero temperature in the normal phase (non pion superfluid state). The stability condition is achieved when the in-media pion width vanishes. However, thermal fluctuations…
We investigate the viability of a new type of compact star whose main constituent is a Bose-Einstein condensate of charged pions. Several different setups are considered, where a gas of charged leptons and neutrinos is also present. The…
We study self-gravitating multi-pion systems (pion stars) in a state of the Bose condensate. To ensure stability of such stars, it is assumed that they are immersed in the lepton background. Two different phenomenological equations of state…
In the context of the standard model of particle physics, there is a definite upper limit to the density of stable compact stars. However, if a more fundamental level of elementary particles exists, in the form of preons, stability may be…
A new scenario for neutron-star cooling is proposed, based on the correspondence between pion condensation, occurring in neutron matter due to critical spin-isospin fluctuations, and the metal-insulator phase transition in a two-dimensional…
The possibility of the pion condensation phenomenon in cold and electrically neutral dense baryonic matter is investigated in $\beta$-equilibrium. For simplicity, the consideration is performed in the framework of a NJL model with two quark…
Particle number fluctuations are studied in the ideal pion gas approaching Bose-Einstein condensation. Two different cases are considered: Bose condensation of pions at large charge densities $\rho_Q$ and Bose condensation at large total…
Recently it was pointed out that coherent or condensated states of pions may account for the explanation of the Centauro events observed in cosmic ray showers. We argue that an occurrence of condensed pions requires that the system evolves…
We perform a stability analysis of the homogeneous ground state of nuclear matter against inhomogeneous perturbations of the pion condensate. In $\beta$-equilibrium, restricting the baryon species to nucleons only, we observe no…
We examine the behavior of charged pions in neutron-rich matter using heavy-baryon chiral perturbation theory. This study is motivated by the prospect that pions, or pion-like excitations, may be relevant in neutron-rich matter encountered…
Recent studies on meson condensations (pions and kaons) in high-density hadronic matter are reviewed. After summarizing onset mechanisms of pion and kaon condensations, we discuss implications for neutron star phenomena such as rapid…
Pion stars consisting of Bose-Einstein condensed charged pions have recently been proposed as a new class of compact stars. We use the two-particle irreducible effective action to leading order in the $1/N$-expansion to describe charged and…
We present microcanonical ensemble calculations of particle number fluctuations in the ideal pion gas approaching Bose-Einstein condensation. In the samples of events with a fixed number of all pions, $N_{\pi}$, one may observe a prominent…
Coherent pion production in low energy neutrino reactions is discussed in the framework of the partially conserved axial vector current theory (PCAC). The role of lepton mass effects in suppressing production of positively charged pions is…
After the first predictions in seventies that in dense nuclear matter, for example, in neutron stars there could be pion condensation phenomenon, it was shown that at least s-wave pion condensation is unlikely to occur in such a medium in…
A collection of modern, field-theoretical equations of state is applied to the investigation of cooling properties of compact stars. These comprise neutron stars as well as hypothetical strange matter stars, made up of absolutely stable…
We studied thermal evolution of isolated neutron stars (NSs) including the pion condensation core, with an emphasis on the stiffness of equation of state (EOS). Many temperature observations can be explained by the minimal cooling scenario…
The merger of two neutron stars probes dense matter in a hot, neutrino-trapped regime. In this work, we investigate how fully accounting for pions, muons, and muon-type neutrinos in the trapped regime may affect the outcome of the merger.…
Local fluctuations of pion density in momentum space may lead to Bose-Einstein condensation. Conditions for this phenomenon to occur in in high-energy collisions and possibilities of its experimental investigation are discussed.